Ruggedized high frequency apparatus



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Feb. 6, 1968 c. F. DOUGLASS 3,368,163

I RUGGEDZED HIGH FREQUENCY APPARATUS Filed May 28, 1964 f3.5 3 ..87 "Q /91 f9.3

INVENTQR CHAR; Es E Doz/GLASS ATTORN EY United States Patent Office Sdbg Patented Feb. 6, 1968 3,368,163 RUGGEDHZED HIGH FREQUENCY APPARATUS Charles F. Douglass, Emporium, Pa., assigner to Sylvania Electric Products Inc., a corporation of Delaware Filed May 28, 1964, Ser. No. 371,025 7 Claims. (Cl. 331-98) ABSTRACT F THE DESCLQSURE Ultra-high frequency apparatus includes an electron discharge device having a disc-shaped lead-in normal to and passing through an envelope with a plurality of spaced apertures in the lead-in external to the envelope. Also, a resonator includes a pair of cylinders each having a ring-like end with circumferentially spaced holes therein. The apertures of the lead-in are aligned with the holes of the cylinders to provide means for aflixing the cylinders to opposite surfaces of the lead-in and a feedback path intermediate the cylinders of the resonator.

This invention relates to ultra-high frequency apparatus and more particularly to apparatus which includes an electron discharge device having a disc-shaped leadin and a cavity resonator suitable for use therewith.

Numerous types of apparatus suitable for use at ultrahigh frequencies are available, and one of the more common varieties includes an electron discharge device and a cavity resonator, The discharge device is very often a so-called pencil type tube which is an elongated structure having metallic anode and cathode portions separated by an insulating envelope. A disc-shaped lead-in is disposed in a plane substantially normal to the longitudinal axis of the tube and is sealed to and passes through the envelope. Usually the lead-in has a central portion within the envelope to which is attached a grid electrode and an annular portion external to the envelope adapted for electrical and mechanical attachment thereto.

Of the known types of cavity resonators suitable for use with the pencil type tube, the most frequently encountered is a split hollow cylinder with a plunger assembly inserted at each end, a probe extending from the cylinder whereby the signal is conveyed, and a means for reducing the diameter of the cylinder. The cylinder is usually of a material such as low carbon steel and the plunger assemblies are insulated therefrom by a spacer and in slidable engagement therewith.

As to the assembly of the apparatus, the pencil tube is inserted within the cylinder and a plunger assembly is telescoped over the anode and cathode portions respectively. These assemblies are longitudinally adjusted to obtain the desired operational characteristics of the apparatus, and then the diameter of the cylinder is reduced. Upon reduction of the cylinder diameter, the cylinder wall exerts a pressure on the peripheral surface of the disc-shaped lead-in and the plunger assemblies by way of the insulating spacers thereon. Thus, the predetermined spacial relationship of the discharge device and resonator, as well as the operational characteristic of the apparatus, are maintained by the pressure exerted when the diameter of the cylinder is reduced.

Additionally, when the apparatus is to be used in an oscillator application, it becomes necessary to provide a path for feedback between the sections of the resonator separated by the disc-shaped lead-in. In the known apparatus, a feedback path is provided by a spring-like structure having a plurality of straight sides and corner portions. This structure is disposed intermediate the peripheral surface of the lead-in and the inner wall of the cylinder such that the pressure exerted between the cylinder and the peripheral surface of the lead-in determines the amount of deflection of the spring-like structure and consequently the feedback path between the adjacent sections of the resonator.

While such apparatus appears to be adequate for many of the ordinary and reasonably average conditions of operation, it has been found that an adverse environment, excessive vibration, unusual acceleration, and a high level of shock have a deleterious effect upon the operational performance of such apparatus. For example, when such apparatus is subjected to an adverse environmental condition, such as a Wide variation in temperature, the diameter of the cylinder changes due to the expansion or contraction of the metal. As a result, the pressure exerted on the peripheral surface of the disc-shaped lead-in which maintains the relatively heavy discharge device at a fixed location is reduced, and the discharge device has a tendency to move longitudinally within the cavity resonator when the apparatus is suddenly accelerated. Also, when such apparatus is operated in an oscillator application, the change in pressure due to the expansion or contraction of the cylinder causes a dimensional change in the feedback path intermediate the adjacent cavity sections and a resulting shift in the operational frequency of the oscillator.

Additionally, the anode and cathode plunger assemblies are maintained at a fixed location by the pressure exerted from the metal cylinder. This, a relaxation in pressure applied to the assemblies permits a longitudinal movement thereof and a frequency shift of the apparatus which is deleterious to the desired operational use of the device.

Therefore, it is an object of this invention to enhance the dependability of an ultra-high frequency apparatus subjected to adverse environmental conditions.

Another object of the invention is to improve the rigidity and ruggedness of an ultra-high frequency apparatus which includes an electron discharge device and a cavity resonator.

Still another object of the invention is to provide an electron discharge device and a cavity resonator having a means for ruggedized attachment therebetween.

A further object of the invention is to provide a cavity resonator having an improved means of attachment to an electron discharge device.

A still further object of the invention is to provide an electron discharge device suitable for use at ultra-high frequencies having an improved means of attachment to a cavity resonator.

These and other objects are achieved in one aspect of the invention by an electron discharge device having a disc-type lead-in with a plurality of circumferentially spaced apertures in the annular portion thereof and a cavity resonator having a pair of hollow cylinders of a metal having a low coefficient of linear expansion with a ring-like end on each cylinder. Each of the ends has a plurality of circumferentially spaced holes alignable with the apertures of the lead-in, and the ends of the cylinders are attached to opposite surfaces of the lead-in. Also, each cylinder has a plunger assembly in the end thereof, and these assemblies are tixedly attached to the discharge device.

For a better understanding of the present invention, together with other and further objects, advantages, and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings in which:

FIG. l is a transverse sectional view of an ultra-high frequency apparatus including an electron discharge device and a cavity resonator;

FIG. 2 is a plan view of the disc-shaped lead-in; and

FIG. 3 is an isometric view of a cylindrical portion of the cavity resonator.

Referring to FIG. 1 of the drawings, an ultra-high frequency apparatus 3 includes an electron discharge device 5 and a cavity resonator 7. The discharge device 5 includes a metal anode portion 9, a metal cathode portion 11, an insulator envelope 13, and a disc-shaped lead-in 15. The resonator 7 includes a pair of hollow cylinders 17 and 19, a pair of plunger assemblies 21 and 23, and a signal output assembly 25.

In the discharge device 5, the anode portion 9 has a metal tube 27 with an otfset 29 whereto one end of the envelope 13 is hermetically sealed. An exhaust tubulation 31 having a pinched o seal 33 is disposed within the tube 27 and facilitates the evacuation of the envelope 13. The cathode portion 11 includes an outer metal sleeve 35 having an offset 37 whereto the opposite end of the envelope is hermetically sealed and 4contains a substantially U-shaped support 39 force fitted therein. The support 39 has an aperture 41 in the substantially lclosed end 43 thereof, and the open end 45 `rests on an insulating wafer 47 hermetically sealed into the metal tube 27. The wafer 45, which may be glass for example, has a plurality of electrical conductors 49 sealed therein and extending therethrough to which an insulator-covered heater 51 is attached. The heater extends through the aperture 41 of the support 39 and into a cathode assembly 53.

The cathode assembly 53 includes a first `and second tubular section 55 and 57 coaxially disposed and joined by welding or similar means for attaching tubular metals. The section 55 is attached to the support 39 surrounding the central aperture 41 therein and is of a low heat conductivity material in order to reduce the loss of heat by conduction from the second section 57. This second section 57 is preferably of a high heat conductivity material and in conjunction with a layer 59 of emissive material thereon provides the electron source for the discharge device 5. The assembly 53 extends longitudinally upward from the support 39 and passes through a central aperture 61 in a disc-shaped lead-in 15 and into the metal tube 27 of the anode portion 9.

The disc-shaped lead-in 15 is disposed in a plane substantially normal to the longitudinal axis of the envelope 13 and passes therethrough and is hermetically sealed thereto at a plurality of jointures 63, 65, 67, and 69. As mentioned above, the lead-in 15 has a central aperture 61, and an upstanding tubular-shaped grid electrode 71 is attached at one end thereto surrounding the aperture 61. This electrode 71 extends upwardly unto the anode portion 9 and surrounds the second section 57 of the cathode assembly 53. Also, the disc-shaped lead-in 15 includes an annular section 63 external to and surrounding the envelope 13 as can be more readily seen in FIG. 2.

Herein, the disc-shaped lead-in 15 includes a central aperture 61, an annular portion 71, and a plurality of circumferentially spaced apertures 73 spaced from and surrounding the central aperture 61. As will be explained hereinafter, these apertures 73 not only serve to facilitate a ruggedized connection between the discharge device 5 and the resonator 7 but also provide a feedback path between adjacent sections of the resonator 7 which is substantially unaltered by environmental conditions when the apparatus is used in an oscillator application.

As to the cavity resonator 7, the hollow metal cylinders 17 and 19 may be best illustrated with reference to FIG. 3. Each of the cylinders 17 and 19 has a ring-like end 77 in a plane substantially normal to the longitudinal axis thereof which surrounds a central hole 79. A plurality of circumferentially spaced holes 81 surround and are spaced from the central hole 79 in each of the cylinders 17 and 19. The central hole 79 of each of the cylinders 17 and 19 is adapted to telescope over the anode and cathode portions 9 and 11 respectively whereupon the ring-like end 77 contacts opposite surfaces of the annular section 63 of the disc-shaped lead-in 15.

The circumferentially spaced holes 81 are alignable with the circumferentially spaced apertures 75, and a con- 4 necting means 83 rigidly attaches the ring-like ends 77 of the cylinders 17 and 19 to the lead-in 15. Although numerous techniques are available for attaching the cylinders 17 and 19 to the lead-in 15, a preferred and convenient method is to pass several bolts through some of the apertures and holes 81 as illustrated in FIG. 1.

Additionally, a preferred material for the cylinders 17 and 19 is known as Invar, and a description thereof is readily available on page 1433 of the Handbook of Chemistry and Physics, thirty-seventh edition, 1955-1956. Such a material has a relatively low coeicient of linear expansion and, because of this characteristic, provides a reduced amount of frequency shift variation in the apparatus 3 under adverse environments wherein the variation in temperature is relatively great. Other materials are also applicable and appropriate so long as they have coefficient of linear expansion in the range of about 0.7 to 4.0 106 inches F.

At the end opposite to the ring-like end 77 of the cylinder 17 is a metallic plunger assembly 21 telescoped over the anode portion 9 of the discharge device 5. This assembly Z1 includes a spring-like tubular sleeve 85 adapted for slidable contact with the anode portion 9 and ixedly attached thereto by welding, cementing, or any one of a number of well-known attaching methods after the operational conditions of the apparatus 3 has been satisfied. A plunger 87 has a centrally apertured upstanding side portion 89 force fitted onto the sleeve 85 and downwardly extending circular sides 91 encompassed by an insulating spacer 93v in slidable engagement with the inner wall of the cylinder 17.

In a similar manner, a plunger assembly 23 is contained within the end opposite to the ring-like end 77 of.

the cylinder 19. This assembly 23 is telescoped over the cathode portion 11 of the discharge device 5 and includes a second spring-like tubular sleeve 95 adapted for slidable contact with the cathode portion 11 and fixedly attached thereto in a manner and at a time such as previously described. A second plunger 97 has a centrally apertured upstanding side portion 99 force fitted onto the sleeve 915 and circular sides 1111 encircled with au insulating spacer 103 in slidable engagement with the iuner wall of the cylinder 19.

Additionally, the cylinder 17 has a signal output assembly 25 affixed thereto as a means for transferring a signal from within the cavity 7 to external auxiliary apparatus (not shown). Although numerous types of assemblies are applicable and appropriate, a preferred assembly 25 is a coaxial connector 105 having an external thread 107 fitted into and through an internally threaded protuberance 109 yattached to the cylinder 17 at a jointure 111 surrounding an aperture 113 in the cylinder 17. This assembly 25 provides a very rigid and substantially immobile signal output connection even under adverse conditions of vibration, acceleration, and environment.

As to the assembly and adjustment of t-he ultra-high frequency apparatus 3, the hollow cylinders 17 and 19 are telescoped over the anode and cathode portions 9 and 11 respectively of the discharge device 5, and the ring-like end 77 of the cylinders 17 and 19 is placed in Contact with opposite surfaces of the annular portion 73 of the lead-in 15. The circumferentially spaced holes 81 are brought into alignment with the circumferentially spaced apertures 75 and attached thereto by way of a connecting means 83.

Thereafter, the plunger assemblies 21 and 23 are telescoped over the anode and cathode portions 9 and 11 and within the cylinders 17 and 19 respectively. These assemblies 21 and 23 are longitudinally adjusted until the desired operational characteristics of the apparatus 3 are obtained and then lixedly attached to the anode and cathode portions 9 and 11.

It is to be noted that the apparatus 3 has a substantially unbroken circumferential surface in the vicinity of the disc-shaped lead-in 15 and the rigidity with which the discharge device 5 is held Within the resonator 7 is no longer dependent upon the pressure exerted on the peripheral surface of the lead-in by the resonator 7. Further, when the apparatus is used in an oscillator application, the necessary feedback path between the anode and the cathode portions 9 and 11 is no longer subject to variation in size because of the linear expansion and contraction of the cavity 7.

To further minimize the shift in operational frequency of the apparatus, the cylinders 17 and 19 are of a material having a low coefficient of expansion in the range of about 0.7 to 4.\0 1O6 inches as previously mentioned. Also, the plunger assemblies 21 and 23', which are placed in slidable engagement until the operational conditions are satisfied, are iixedly attached and no longer subject to longitudinal movement because of adverse environment, vibration, and various similar factors.

While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein wit-hout departing from the invention as defined by the appended claims.

What is claimed is:

1. Ultra-high frequency apparatus including an electron discharge device and a cavity resonator, said discharge device having a tubular insulating envelope and a metallic disc-shaped lead-in passing therethrough normal to the longitudinal axis thereof, said lead-in comprising a central portion within said envelope and an annular portion external to said envelope, said annular portion having a plurality of circumferentially spaced apertures; and said resonator having a pair of hollow metallic cylinders with each cylinder having a ring-like end normal to the longitudinal axis of said cylinder and each ring-like end of said cylinders having a plurality of circumferentially spaced holes and being attached to an opposite surface of said annular portion of said lead-in, said circumferentially spaced holes and apertures being longitudinally aligned to provide a feedback path between the resonator sections.

2. Ultra-high frequency apparatus including an electron discharge device and a cavity resonator, said discharge device having a tubular insulating envelope, a tubular metallic anode portion sealed to one end of said envelope, a tubular metallic cathode portion sealed to the opposite end of said envelope, and a metallic disc-shaped lead-in sealed to and extending through said envelope intermediate said anode and said cathode portions, said disc-shaped lead-in being in a plane substantially normal to the longitudinal axis of said envelope and said anode and cathode portions, and having a centrally located aperturel wit-hin said envelope and a plurality of circumferentially spaced apertures external to said envelope; and said resonator having a pair of hollow metal cylinders with each of said cylinders having a ring-like end and each end having a central hole and a plurality of circumferentially spaced holes surrounding and spaced from said central hole, said circumferentially spaced holes in said end of said cylinders being aligned with said circumferentially spaced apertures in said disc-shaped lead-in and each of said ends of said cylinders being attached to an opposite surface of said disc-shaped lead-in, a plunger assembly within each cylinder and spaced from said end thereof, one of said plungers being attached to said anode portion and insulated from said cylinder by an insulating spacer and the other of said plungers being attached to said cathode portion and insulated from said cylinder by a second insulating spacer, and a high frequency probe within and extending from said resonator.

3. Ultra-high frequency apparatus including an electron discharge device and a cavity resonator, said discharge device having a tubular insulating envelope, a tubular metallic anode portion sealed to one end of said envelope, a tubular metallic cathode portion sealed to the opposite end of said envelope, and a metallic disc-shaped lead-in sealed to and extending through said envelope intermediate said anode portion and said cathode portion, said disc-shaped lead-in being in a plane substantially normal to the longitudinal axis of said envelope and said anode and cathode portions and having a centrally located aperture within said envelope and a plurality of circumferentially spaced apertures external to said envelope; and said resonator having a pair of hollow metal cylinders of a material having a coeicient of expansion in the range of about 0.7 to 4.0 106 inches/ =F. to provide a substantially uniform cylinder diameter and area contained thereby in an environment of adverse temperature, each of said cylinders having a ring-like end substantially normal to the longitudinal axis thereof and each end having a central hole and a plurality of circumferentially spaced holes surrounding and spaced from said central hole, said holes in said ends being aligned with said apertures in said disc-shaped lead-in and each ring-like end of said cylinders being attached to an opposite surface of said disc-shaped lead-in, a plunger assembly within each cylinder and spaced from said end, one of said plunger assemblies being attached to said anode portion and insulated from said cylinder by an insulating spacer and the other of said plunger assemblies being attached to said cathode portion and insulated from said cylinder by a second insulating spacer, and a high frequency probe within and extending from said resonator.

4. An electron disc-harge device suitable for use at ultra-high frequencies and including a tubular envelope of insulating material and a metallic disc-shaped lead-in sealed thereto and passing therethrough in a plane substantially normal to the longitudinal axis of said envelope, said lead-in comprising an apertured central portion within said envelope and an annular portion external to said envelope, said annular portion having a plurality of circumferentially spaced apertures for rigidly attaching a circuit element to said annular portion and providing feedback between adjacent sections of a said circuit element.

5. An electron discharge device suitable for use at ultra-high frequencies comprising a tubular envelope of insulating material, a tubular metallic anode portion sealed to one end of said envelope, a tubular metallic cathode portion sealed to the opposite end of said envelope, and a metallic disc-shaped lead-in sealed to and passing through said envelope intermediate said anode and said cathode portions, said disc-shaped lead-in being in a plane substantially normal to the longitudinal axis o-f said envelope land having an apertured central portion within said envelope and an annular portion external to said envelope, said annular portion having a plurality of circumferentially spaced apertures for rigidly `attaching a circuit element to said annular portion and providing feedback between adjacent sections of said circuit element.

6. A cavity resonator adapted for use with an elongated electron discharge device having a metallic disc-shaped lead-in with a plurality of circumferentially spaced apertures therein and disposed in a plane normal to the longitudinal axis of said resonator comprising a pair of hollow metallic cylinders with each cylinder having a ring-like end substantially normal to the longitudinal axis of said cylinder, each ring-like end having a central hole and a plurality of circumferentially spaced holes surrounding and spaced from said central hole with each end being adapted for attachment to an opposite surface of said disc-shaped lead-in, said spaced holes being aligned with said apertures of said lead-in whereby said circumferentially spaced holes and apertures provide means for rigidly attaching said end portions of said cylinders to opposite surfaces of said disc-shaped lead-in and means for energy feedback between adjacent sections of said resonator.

7. A cavity resonator adapted for use with an elongated electron discharge device having a metallic disc-shaped lead-in disposed in a plane substantially normal to the longitudinal axis of said discharge device and having a plurality of circumferentially spaced apertures therein comprising a pair of hollow cylinders of a material having a coefcient of expansion in the range of about 0.7 to 4.O 106 inches/ F. to provide a substantially uniform cylinder diameter .and area contained thereby in an environment of adverse temperature with each cylinder having a ring-like end substantially normal to the longitudinal axis of said cylinder, said end of said cylinders having a central hole and a plurality of circumferentially spaced holes surrounding and spaced from said central hole and adapted for attachment to an opposite surface of said discshaped lead-in with said spaced holes in alignment with said apertures; a plunger assembly Within each of said cylinders and insulated therefrom by a spacer, each of said plunger assemblies being spaced from said end portion of said cylinder and rigidly attached to said discharge device; and a high frequency probe Within said resonator and extending therefrom.

References Cited UNITED STATES PATENTS HERMAN KARL SAALBACH, Primary Examiner.

ELI LIEBERMAN, Examiner.

15 S. CHATMON, JR., Assistant Examiner. 

